1. Field of the Invention
The present invention relates to a connector to be connected with a flat flexible cable such as an FPC (Flexible Printed Circuit) and an FFC (Flexible Flat Cable), which are generically called FPC in this specification, and particularly to a ZIF (Zero Insertion Force) type connector for a FPC which requires little force for insertion and removal of the FPC.
2. Related Art
A connector for an FPC to be surface-mounted on a printed circuit board, or a surface mount connector for an FPC has an insulated housing formed with an insertion portion for inserting the FPC and a plurality of contacts fitted onto the housing side by side in a line at predetermined pitches. To bring the FPC into touch with the contacts, for example, an opening and closing cover housing is provided at the insertion portion.
As such a connector for an FPC, there has been invented a connector for an FPC capable of attaining a stable pressing force against the FPC by increasing the strength of a cover housing pressing a plurality of contacts against the FPC and capable of being connected whether the conductor pattern of the FPC is in an upward or downward position. (For example, refer to Patent Documents 1 below.)
Furthermore, as such a connector for FPC, there has been also invented an upper contact type connector for an FPC capable of ensuring sufficient contact pressure against the FPC by preventing the contacts from being excessively deformed. (For example, refer to Patent Document 2 below.)
Patent Document 1: Japanese Unexamined Patent Application Publication No. Hei 11-185896
Patent Document 2: Japanese Unexamined Patent Application Publication No. 2001-126793
FIG. 13 is a longitudinal sectional view of a connector for an FPC according to Patent Document 1 illustrating a constitutional view including an FPC with a cover housing in an open position. FIG. 13 used herein corresponds to FIG. 4 in Patent Document 1.
As shown in FIG. 13, a connector 8 includes a housing 82, a plurality of contacts 83, a cover housing 84 and a plurality of cover contacts 820. The housing 82 is formed with an opening 87 open upwards. The plurality of contacts 83 are stored and retained in the housing 82 at regular pitches, and a contact portion 817 of an elastic contact beam 814 is disposed at the opening 87. The plurality of contacts 83 includes an arm 815 and an elastic contact beam 814, and the arm 815 is formed integrally with the elastic contact beam 814. The arm 815 extends to the opening 87 along an upper wall 86 of the housing 82, and the front end thereof is formed with a pivotal support portion 818. The pivotal support portion 818 faces the contact portion 817.
As shown in FIG. 13, the cover housing 84 is supported, engaged with the pivotal support portion 818 and moves between a pressure position in proximity to the contact portion 817 and an open position separated from the contact portion 817. When the cover housing 84 is moved toward a pressure position, FPC 1 disposed on the elastic contact beam 814 is pressed against the elastic contact beam 814. The plurality of cover contacts 820 are arranged on the inside of the cover housing 84, corresponding to the contacts 83, and are engaged with the pivotal support portion 818. The plurality of cover contacts 820 are pressed against FPC 1 for contact at a pressurizing position, and comes into contact with the pivotal support portion 818 for electrical continuity.
FIGS. 14A and 14B are longitudinal sectional views of a connector for an FPC according to Patent Document 2, and FIG. 14A is a longitudinal sectional view of the whole connector and FIG. 14B is an enlarged view of the principal part of FIG. 14A. FIGS. 14A and 14B used herein corresponds to FIG. 5 of Patent Document 2.
As shown in FIGS. 14A and 14B, a connector 9 includes a housing 94, a plurality of tuning-fork-shaped contacts 923 and a cover housing 97. A housing 94 is formed with an opening 96 open upwards. A plurality of contacts 923 are arranged so as to face the opening 96 in the housing 94. The contacts 923 includes an elastic piece 935 positioned on the upper side and a stationary piece 933 positioned on the lower side, the elastic piece 935 and the stationary piece 933 facing each other. The cover housing 97 is pivotally supported by the pivotal support portion (not shown) of the housing 94 or a member retained on the housing 94, and opens or closes the opening 96 with rotation thereof.
As shown in FIG. 14A or 14B, the free end of the elastic piece 935 has an upper branch piece 939 and a lower branch piece 941 branching in a roughly C shape. The lower branch piece 941 includes a contact 948 coming into pressure contact with FPC 1. One end of the cover housing 97 is disposed between the upper branch piece 939 and the lower branch piece 941 to regulate a displacement range of the elastic piece 935. The one end of the cover housing 97 includes a cam surface 959 pushing up the upper branch piece 939 so as to expand an insertion space 93 for FPC 1 below the contact 948.
As shown in FIG. 13, the cover contact 820 is produced by punching a metal sheet in the same way as for the contact 83 and is formed integrally with the cover housing 84 by means of insert molding at the time of forming the synthetic resin cover housing 84.
As shown in FIG. 14A or 14B, a pair of pivotal spindles (not shown) having a pivotal axial line A1 is provided on both ends of a metal wire 945 embedded in the cover housing 97. Moreover, a metal reinforcing wire 951 is embedded in the cover housing 97. To insert the metal wires 945, 951 into the synthetic resin cover housing 97 at the time of forming them into the synthetic resin cover housing 97 and embed them into a molded product of the cover housing 97, the metal wires 945, 951 are supported at a predetermined position within a metallic mold.
A connector for the FPC which has a FPC conductor pattern facing upwards or which is of an upper contact type, as shown in Patent Documents 1 and 2, prevents deformation of the cover housing by insert molding (integrally forming) a metal member into the synthetic resin cover housing.
However, such integrally molded products including metal members cause higher costs in production than molded products made of synthetic resin alone. As a matter of course, an increase in the number of components causes higher costs. This is because supporting a metal member in a predetermined position within a metal mold requires much production time per product and causes difficulty in simultaneously forming a plurality of products. An increase in the cost of a cover housing leads to a higher cost of the connector for an FPC.
Attainment of a molded cover housing made of synthetic resin alone by devising a structure of an upper contact type connector for an FPC can reduce the production cost of the connector. As a connector for an FPC having the multi-pin contacts and narrow pitches, a connector for FPC is required which has a structure capable of completely maintaining an open/closed position without deforming the cover housing. These are problems addressed by the present invention.